Transformation of ameloblastic fibroma to fibrosarcoma.

The direct transformation of an ameloblastic fibroma into a fibrosarcoma in a 16-year-old Caucasian male is reported. Although no ameloblastic epithelium was found in the recurrent tumor, the odontogenic origin of the fibrosarcoma was evident. The ameloblastic fibrosarcoma and the fibrosarcoma of identical odontogenic origin represent an entity which should be distinguished from conventional fibrosarcoma as these tumors demonstrate different clinical behaviors.